The University of Dayton conducted a feasibility study of the application of inorganic oxides as the best energy storage media for thermal energy storage devices. The thermophysical properties of the heat of fusion and the melting temperatures of the pure inorganic oxides were reviewed and evaluated. A total of nine inorganic oxides were identified which have a value for the heat of fusion greater than 793.7 Joules per gram (100 watt-hours per pound). However, all of the melting points of these nine oxides are greater than 1570 C. Since none of these pure materials had a melting point in the desired temperature interval of 538 C to 760 C (1000 F to 1400 F), the phase diagrams of binary inorganic oxides were reviewed. The study of binary inorganic oxide systems was limited to those systems which contain at least one of the nine pure oxides which have a liquid-solid transformation in the required temperature interval. The binary system comprised of dilithium oxide and diboron trioxide was assessed as having the highest potential.